The invention relates to single component silicone compositions which cure at room temperature to form elastomeric products. More particularly the invention relates to room temperature vulcanizable (RTV) silicone rubber compositions containing aminohydrocarbyl-substituted ketoximino silanes as adhesion promoters to attain an improved crack resistance during cure, as well as improved stability of cure during shelflife.
U.S. Pat. No. 3,189,576 describes certain oxime silanes as useful intermediates in one component room temperature curing coating and caulking applications. The disclosed class of organosilicons consists of oxime substituents including methyl ethyl ketoxime. However, aminohydrocarbyl-substituted ketoximino silanes are not disclosed. U.S. Pat. No. 4,705,877 describes aminohydrocarbyl substituted ketoximinosilanes as coupling agents, however, no use as an adhesion promoter in room temperature vulcanizable silicone rubber compositions is suggested. Many other patents issued to date describe the usefulness of oxime silanes as crosslinkers and methods of compounding RTV caulking materials with oxime silanes. It is also known in the art to use organofunctional silanes as adhesion promoters for ketoximino silane crosslinked one component RTV's. U.S. Pat. No. 4,720,530 teaches one component silicone RTV using ketoximinosilanes as crosslinkers and aminoalkylalkoxy silanes as adhesion promoters. Not known in the art however, is the use or advantage of aminohydrocarbyl-substituted ketoximino silanes as an adhesion promoter in one component room temperature vulcanizing silicone sealants. This invention has found the advantage of aminohydrocarbyl-substituted ketoximino silanes as adhesion promoters in one component room temperature vulcanizing silicone sealants which also use ketoximino silanes or alkoxy-ketoximino silanes as crosslinkers.